液相色谱-串联质谱法检测水产品中残留的硝基呋喃类药物的代谢物

建立了液相色谱-串联质谱(LC-MS/MS)法用于同时测定水产品中硝基呋喃类药物的代谢物3-氨基-2-唑烷基酮(AOZ)、5-甲基吗啉-3-氨基-2-唑烷基酮(AMOZ)、氨基脲(SEM)、1-氨基-2-内酰脲(AHD)和3,5-二硝基水杨酸肼(DNSH)。样品经盐酸水解、2-硝基苯甲醛衍生、乙酸乙酯提取净化。氮吹至干后,用1 mL乙腈-0.1%甲酸水(20:80, v/v)定容。经Aquasil C18色谱柱分离,用液相色谱-三重四极杆串联质谱以多反应监测模式(MRM)进行检测分析,内标法定量。结果表明,该方法的线性范围为0.5～10 μg/kg, 5种代谢物的线性相关系数均不小于0.9976,定量限为0.5 μg/kg。在0.5、1.0、2.0和4.0 μg/kg的添加水平下,加标回收率为81.3%～100.5%, RSD为3.4%～10.0%。本法可作为水产品中5种硝基呋喃类药物的代谢物残留量同时分析的有效手段。

Determination of metabolite residues of nitrofuran antibiotics in aquatic products by liquid chromatography-tandem mass spectrometry

A method was developed for simultaneous qualitative and quantitative analysis of five metabolites of nitrofuran antibiotics, including 3-amino-2-oxazolidinone (AOZ), 5-morpholino-methyl-3-amino-2-oxazolidinone (AMOZ), semicarbazide (SEM), 1-aminohydantoin (AHD) and 3,5-dinitrosalicylic acid hydrazide (DNSH) in aquatic products by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were hydrolyzed with HCl, and derivatized with 2-nitrobenzaldehyde at 37 ℃ for 16 hours. The derivative solutions were adjusted to pH 7.0-7.5, and the analytes were extracted by ethyl acetate. The separation was based on Thermo Aquasil C18 column (150 mm×4.6 mm, 3.0 μm). The analytes were detected by tandem mass spectrometry with electrospray ionization source with multiple reaction monitoring (MRM) mode. The developed method showed good linear correlation between the peak area ratios of the analyte and the internal standard and the concentration of the analyte with the correlation coefficients all above 0.99 over the dynamic range of 0.5-10 μg/kg. The limits of quantitation (LOQs) of AOZ, AMOZ, SEM, AHD and DNSH were 0.5 μg/kg. The average recoveries of all the compounds at four spiked levels of 0.5, 1.0, 2.0 and 4.0 μg/kg ranged from 81.3% to 100.5% with the RSDs between 3.4% and 10.0% (n=6). The method is proved to be fast and effective for simultaneous qualitative and quantitative analysis of the metabolites of the nitrofuran antibiotics in aquatic products.